Substrate coated with a layer of polyquaternary polyelectrolytes

ABSTRACT

A substrate such as paper is coated with a layer of polyquaternary polyelectrolyte formed by the polymerization in absence of oxygen of a monomer of the general formula:   where x is 3 or more than 6 and Z is I, Br or Cl to form high charge density linear polymers. Segements of the linear polymer may be attached to or formed in the presence of polyfunctional reactive tertiary amines or halogen polymeric substrates or polyfunctional lower molecular reactive polyfunctional substrates to form branched or star polyelectrolytes by quaternization polymerization reaction.

United States Patent Rembaum et a1.

[ Dec. 16, 1975 SUBSTRATE COATED WITH A LAYER OF POLYQUATERNARYPOLYELECTROLYTES Inventors: Alan Rembaum; Shiao-Ping Siao Yen, both ofAltadena, Calif.

California Institute of Technology, Pasadena, Calif.

Filed: Dec. 26, 1973 Appl. No.: 427,916

Related US, Application Data Division of Ser. No. 280,649, Aug. 14,1972.

Assignee:

US. Cl 428/411; 260/2 R; 260/823; 260/874; 428/511; 428/537 Int. C1...B32B 21/04; B32B 21/06; B32B 23/08; B32B 27/10 Field of Search 117/155UA, 161 UT; 260/2 R, 876 B, 878 B, 879, 880 B, 823, 874; 428/411, 511,537

References Cited UNITED STATES PATENTS 6/1967 Michaels 117/155 X 9/1968Wessling et a1 117/155 X 11/1971 Werdauschegg et a1 117/155 X 3,632,507l/l972 Witt 210/54 3,754,055 8/1973 Rembaum 117/155 X FOREIGN PATENTS ORAPPLICATIONS 1,126,396 3/1962 Germany 260/2 R Primary Examiner-MichaelR. Lusignan Attorney, Agent, or FirmMarvin E. Jacobs [5 7] ABSTRACT Asubstrate such as paper is coated with a layer of polyquatemarypolyelectrolyte formed by the polymerization in absence of oxygen of amonomer of the general formula:

9 Claims, N0 Drawings SUBSTRATE COATED WITH A LAYER oF POLYQUATERNARYPOLYELECTROLYTES CROSS REFERENCE TO RELATED APPLICATION This applicationis a division of Ser. No. 280,649, filed Aug. 14, 1972.

ORIGIN OF THE INVENTION The invention described herein wasmade in theper forrnance of work under a NASA contract and is subject to theprovisions of Section 305 of the National Aeronautics and Space Act of1958, Public Law 83-568 (72 Stat. 435; 42 USC 2457).

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to novel polyelectrolytes. More particularly, the inventionrelates to polyelectrolytes having a high concentration of cationicnitrogen centers.

2. Description of the Prior Art Poly-quaternary ammonium polymericpolyelectrolytes have generally been produced by the copolymerization ofa dihalide and a ditertiary amine. The more desirable short chainmonomers should produce the highest charge density polymers. However,many of the C to C combinations of monomers produce cyclic rather thanlinear polymeric products.

Polyammonium salts can also be formed by the homopolymerization of ABmonomers such as haloalkyl tertiary amines. In German Pat. No. 1,126,396which disclosed the synthesis of an AB monomer of this type, it wasnoted that the AB compound was unstable and whendimethylaminoethylchloride was heated to between 80 and 100C in water, aviscous material was recovered identified as a polyammonium salt.However, it is now known that this compound forms a cyclic 6 memberring.

Gibbs et al, (JACS 55, 753, 1933) polymerizeddimethylaminopropylchloride (DMAP C1) or BR DMAP Br in bulk on a steambath. This procedure is only capable of forming low molecular weightproducts. The molecular weights were determined from the ratio ofnonionic to ionic halogen in the product. This method of determiningmolecular weight is now considered inaccurate and would provide highervalues than the analytical method utilized in the present invention.

High molecular weight polycationic materials having high charge densitywill find many uses such as flocculants in the clarification ofresidential and industrial water supplies, and effluents, as dewateringagents, as flotation agents, as catalyst and pigment retentionadditives, and as gelling agents. Polyelectrolyte materials will alsofind use in the rheological modification of fluids such as frictionreducers, as dispersants for clay and sludge in both aqueous and oilbased systems as well as antistatic agents, the additives to cosmetics,textile finishes and lubricating oils. These materials generally exhibitgermicidal action and are effective bactericidal and fungicidal agents.A further important area of application is in the preparation ofelectroconductive photocopy papers.

All of these applications are dependent on the quaternary ammoniumfunction and the availability and density of the groups. The activity inall cases will be enhanced by improving either or both of thesecharacteristics.

SUMMARY OF THE INVENTION High charge density polymers having a molecularweight above 5000 are produced in accordance with this invention bypolymerization under oxygen excluding conditions of a monomer of theformula:

where x is 3 or more than 6 and Z is I, C1, or Br.

At values of x other than 3 or 7l0 cyclic compounds are formed andlinear homopolymerization does not occur. Monomers such asdimethylaminoethylchloride or cycloalkyl, benzyl or phenyl substitutedamino alkyl halides as taught in German Pat. No. 1,126,396 do not formhomopolymers.

Furthermore, if the monomer of formula I is characterized as an ABmonomer where A is (CI-I N and B is Z then the homopolymer will have theformula:

where n is an integer of at least 200 and the molecular weight ispreferably at least 30,000.

Thus the polymer is always terminated by A and B functional groups. Incontrast polyquaternary polymers prepared from AA, BB monomer mixtureswould form an unresolved mixture of A-A, BB, and A-B terminatedpolymers.

Furthermore, in the A-A, BB polymerization the stoichiometry must beexactly balanced or chain termination occurs. Highly polar solvents mustbe utilized and the high charge density present with monomers such asA(CH A and B(CI-I B also interferes with the production of highmolecular weight, linear chains. Furthermore, the mixed functionality ofthe terminated mixtures prevents formation of star and branched polymersin accordance with the invention.

The branch polymers have a comb-like structure and are formed byattaching a plurality of units of the homopolymer of the invention to apolymeric substrate containing a plurality of functional groups reactivewith either (CH N or Z- of the AB monomer. The polymeric substrate maybe selected from polymers having a repeating structure of the formulae:

R (Illa) (lllb) fined above.

R can be hydrogen. lower alkyl or aryl such as phenyl. R is a shortchain linking group such as lower alkylene. phenylene, alkyl ester andthe like. D is a functional group reactive with either A or B such asnitrogen, (R N or Z where R is an organic group such as lower alkyl,aryl, aralkyl and n is an integer. In the case of Z, R should not bephenyl since the halogen is not sufficiently reactive with the tertiaryamine groups of the AB monomer.

Suitable polymeric substrates are polymers such as poly-4-vinylpyridine, polyethylene imine, polyvinylbenzylchloride,polyepichlorohydrin, polydimethylaminomethyl ethylene oxide,poly-dialkylaminoalkylacrylates such as poly-dimethylaminoethylacrylate, polyalkylaminoacrylamides such as polydimethylaminopropylacrylamide and the like. The polymer may be syndiotactic, isotactic. oratactic.

Star polymers having a molecular weight of at least 5,000 ara formed byattaching radial sections of the homopolymer of this invention to acentral monomer of the formula:

where Y is a central, polyvalent, comparatively low molecular weightorganic group having a valence of 3+m, m is an integer from O to 3, Rand D are as defined above. Y can be an aromatic compound such asbenzene or lower alkylated benzene. Suitable central monomeric compoundsbeing 2,4,6-tri-(chloromethyl )-mesitylene, l ,2,4-trichloromethyl)-benzene and l,2,4,5-tetra-(chloromethyl)-benzene. The two benzenecompounds are prepared from p-xylene in accordance with the proceduredisclosed by M. Kulka, Canadian Journal of Research 23, 106 (1945). Thecentral monomer can also be a polytertiary amine compound such ascompounds of the formula:

where p is an integer from 2 to and R and R are as defined above.

The polymerization reaction in each case involves head-to-tailquatemization reaction of the A-B monomer to form linear chains. Inorder to obtain polymers having a molecular weight above 5,000 andpreferably from 30,000 to at least 60,000 the reaction must be conductedunder oxygen excluding conditions, suitably by deaerating or degassingthe reaction mixture before polymerization and by blanketing thereaction mixture with an inert gas,.such as nitrogen or vacuum duringpolymerization. Preliminary deaeration can be effected by bubblingnitrogen through the reaction mixture for a minimum period or byapplying vacuum to the mixture for a sufficient period beforeapplication of heat. It has been found that carbon dioxide inhibits thequatemization reaction and oxygen causes the formation ofwater-insoluble products.

It is also desirable that the AB monomer be present in the reactionmixture in a relatively high concentration. The rate of reaction and themolecular weight are dependent on monomer concentration and temperature.The monomer concentration is preferably maintained at no less than 2molar and preferably 3-8 molar and the reaction temperature iscontrolled within 40 to 125C, preferably to C. Completion ofpolymerization can be determined by monitoring disappearance orconsumption of monomer.

A preferred AB monomer from the viewpoint of availability, cost,reactivity and high charge density is l,3-dimethylaminopropylchloride.This material is normally furnished commercially as a solidhydrochloride of the formula:

The solid hydrochloride is initially treated with a base such as sodiumhydroxide to convert it to a liquid form. The resulting liquid isinsoluble in water. In a first procedure the water-insoluble, liquidmonomer is converted to a water soluble prepolymer having the structureof formula II by heating the insoluble monomer in alcohol, preferably atreflux and evaporating to dryness to form a low molecular weightprepolymer solid which is soluble in water. This polymer can bedissolved in water and further polymerized to a solid product having amolecular weight above 30,000 and an intrinsic viscosity in 0.40Maqueous KBr of above 0.15 dl/g, typically 0.24 dl/ g.

In an alternative procedure, the insoluble monomer can be dispersed inwater by means of 0.001 to 30% by weight of a nonionic surfactant,suitably difunctional block-polymers terminating a primary alcoholgroups with molecular weights ranging from 1,000 to over 15,000 such asa polyoxyalkylene derivative of propylene glycol or polyvinyl alcohol.Suitable materials are Pluronic R68, RSS, or 6.62 (Wyandotte ChemicalsCorp.).

The branch or star polymers can be formed by indirect or directpolymerization procedures. In a first procedure a stoichiometric amountof AB monomer can be added based on the amount of D to form an adduct ofAB with each D group. Homopolymerization can then proceed forming radialAB polymeric chains from each functional site.

In another procedure the AB monomer is added to the branch polymersubstrate or star nucleus and copolymerized directly to form the highcharge density product radiating polyquatemary sections. In a furtherprocedure, the AB monomer is prepolymerized and the homopolymer isattached to the D sites or the D-AB adduct sites of the branch or starnucleus.

In the case of substrate branch polymers or central star monomers havingresidual reactivity, it is possible to form a water soluble comb-polymeror star polymer intermediate which can be coated onto a substrate orimpregnated into a carrier and then immobilized by heating the productto render the polymer water insoluble. For example,polyvinylbenzylchloride comb polymer forms an insolublized structurewhen heated. Apparently there are unreacted chloromethyl groups presentwhich react with benzene rings on other polymer chains to formcross-links by an alkylation mechanism. This will be very useful inmanufacturing photocopy papers in which the paper can be impregnatedfrom aqueous solution and then heated to convert the polyelectrolyte toa water insoluble form.

The polyelectrolytes of this invention are in each case terminated witha reactive Z or (CH N group. The water soluble polymeric intermediatescan be further reacted with polyfunctional compounds of the formula:

where D is defined above, R is an organic group, and m is a number fromO to 2, to form cross-linked or gelled, water insoluble products.

In the case of a homopolymer, D can be either tertiary amine or chloro,bromo or iodo. In the case of a star or branch polyner, D is selected tobe reactive with the end group of the chain. Thus, a chloro substitutedcentral star monomer or polymer will form chloro terminated chains.Therefore, a diamine would be selected for cross-linking.

Exemplary polyarnines are selected from compounds of the formula:

T7 N ,L.

where R and R are hydrocarbon radicals such as alkyl, aryl or alkenylpreferably containing 1 to 10 carbon atoms or R and R may be joined intoa single hydrocarbon radical. R is a divalent organic radical containingat least 2 carbon atoms such as alkylene, arylene, cycloalkylene,alkenylene, aralkylene, polyoxyalkylene or polythioalkylene. R maycontain 3-100 carbon atoms and may be of prepolymer length.

Exemplary ditertiary aliphatic amines are N, N, N,N-tetramethylhexamethylene diamine or tetramethyldecamethylene diamine.Heterocyclic compounds can also be utilized in which case R and R may becombined. Examples of such ditertiary amino compounds are l,2-bis-(4pyridyl)-ethane or l,2-bis-(4-pyridyl)- ethene. Other ditertiarynitrogen derivatives may be formed from heterocyclic compounds such aspicoline, quinoline, acridine, phenanthn'dine, phenanthroline, orN-alkyl piperidine, pyrrolidone or pyrrole.

Dihalo cross-linking agents may be selected from those of the formula:

ZR5-Z where R is as defined above. Examples of specific compounds are1,3-dibromopropane, 1,4-dibromobutane, l,4 dibromobutane,1,5-dibromopentane, l-lO- dibromodecane, l ,6-dichlorohexane anddibromodimethylbenzene.

The polyelectrolytes of the invention exhibit bacteriostatic as well asbacteriocidal activity when tested by standard clinical proceduresagainst gram positive and gram negative bacteria cultures. Thesolubility of the 6 high molecular weight-polyelectrolytes, therefore,permits formation of a solution which can be topically applied'totraumatic skin areas of the subject such as burns, abrasions or cuts.

Particularly useful compositions an be formed by the addition of asupplemental water soluble film former such as polyvinyl alcohol orpolyvinyl pyrrolidone. The polyelectrolyte may impart elastomericproperties to the final film. The solution is applied to a wound and onevaporation of the water an elastic membrand film is cast. The film isreadily removed by application of water. The solution is also veryeffectively applied to tissue as a spray to achieve a lasting adherentbacteriostatic film which will expand and contract with the movement ofthe tissue. This is very important in the need to exclude air and retainmoisture when dressing burns. Furthermore, the film simultaneouslyexhibits antiseptic, astringent and coagulant activity. The solution canalso be utilized to impregnate gauze materials to form an antiseptic,coagulant, germicidal dressing material.

The polyelectrolytes of this invention can also be dispersed in a waterinsoluble binder. The polyelectrolyte may be compounded and dispersedinto a water insoluble binder such as a polyester, polyamide or vinylresin or the binder may be formed in the presence of thepolyelectrolyte. For example, the polyelectrolyte can be compounded withco-reactive, water soluble, polymers such as polyvinyl alcohol andpolyacrylic acid. The solution may be cast and then heated to form estercross-links between the OH groups of the polyvinyl alcohol and COOl-lgroups of the polyacrylic acid. The final film is water swellable butwater insoluble.

The polyelectrolytes of this invention may also be reacted with anionicpolymers or salts thereof such as polystyrene sulfonates, polyacrylatesand the like and particularly with heparin or its alkali or ammoniumsalts to form ionically-linked, polymeric salts.

The nature of the cross-links is due to an ionic bond between negativegroups on the anionic polymer and the quaternary nitrogen on thepolyelectrolyte. The polymer salts which contain heparin would providenon-thrombogenic surfaces.

Films or membranes can be formed by casting a solution of the copolymersalt and evaporating the solvent. The surfaces of membranes, tubes,catheters, valves, prosthetic veins, etc., can be coated with solutionsof the heparin, copolymer salt and the solvent removed, suitably byvacuum drying to deposit a non-thrombogenic coating. The copolymer saltis compatible with numerous substrates such as Tygon (polyvinyl) Teflon(polytetrafluoroethylene), Dacron (polyester), silicone resins, glass,polystyrene, and polyurethane.

The characteristics of the film or membrane depend on the particularpolyelectrolyte and anionic polymer utilized. The membranes, films ormolded articles may be utilized in water desalination, prosthetic bodyimplants and battery separators.

Polymeric analogs of organic charge transfer complexes can be preparedwhich exhibit high electrical conductivity. For example, the cationicpolyelectrolytes can be combined with 7,7,8,8-tetracyanoquinodimethane(TCNQ) to form salts having high conductivity. The mechanism ofelectronic transport or pseudometallic behavior of the polymeric saltsis not well understood. The salts exhibit high electrical conductivitiesin the presence of lithium TCNQ. On addition of neutral TCNQ theresistivity of the product 7 is dramatically lowered probably caused byincreased electron delocalization. The polyelectrolytes and the saltswith charge transfer complexes thereof will find use as totally organicconductive materials.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examplesillustrate preparation of homopolymers from AB monomers.

EXAMPLE 1 12.1 grams of 1,3-dimethylaminopropylchloride (DMAP Cl) wasadded to 100 ml of absolute alcohol to form a one molar solution of themonomer. The solution was then refluxed under nitrogen for 4 hours.After refluxing, the alcohol solvent was removed by vacuum evaporation.Twelve grams of a prepolymer was obtained which had an intrinsicviscosity of about 0.03 in 0.4 M KBr. Six grams of the low molecularweight prepolymer obtained was then dissolved in 4 ml or water. Thesolution was heated for 4 /2 hours at 95C under a nitrogen atmosphere. Asolid reaction product was isolated which had an intrinsic viscosity of0.21 and is a solid homopolymer having a molecular weight about 20,000.

EXAMPLE 2 26 g of DMAP Cl was reacted with mechanical stirring in 8 mlof H under N at 100C for 4 hours. Upon freeze drying and subsequentvacuum drying at 60C for 24 hours, 18 g of water soluble polymer was obtained (69.2% yield) [17] 0.24 in 0.4 M KBr.

EXAMPLE 3 Following the procedure of Example 2, 26 g of DMAP Cl wasreacted with 8 ml H O in air at 100C for 4 hours. 16 gm of water solublepolymer was obtained (61.5 [1)] =0.146 in 0.4 M KBr.

EXAMPLE 4 Following the procedure of Example 2, 26 gm ofdirnethylaminopropylchloride was reacted in 8 ml H O under 0 at 100C for4 hours. A small amount of white ppt was obtained. The white ppt wasinsoluble in H O (about 1 gm of insoluble polymer 3.9%). The yield ofwater soluble polymer was 65.4% 19 gm) [1;] 0.098.

EXAMPLE The homopolymers branch and star polymers of this invention canbe utilized to form conductive hydrogels having unusually highconductivity. The hydrogels are prepared by reacting a polymer of thisinvention with a gel forming polymer such as polyvinyl alcohol;polyacrylic acid, alginic acids and polyethers. Cross-linked hydrogelscan be prepared from aqueous solutions of a mixture of polyvinyl alcoholand polyacrylic acid or polyhydroxyethylmethacrylate. The hydrogels canbe comprised of from 20 to weight percent of the gel former with theremainder being the polyelectrolyte of this invention. An inertsubstrate such as paper containing from 0.1 to 5 pounds per 1,000 squarefeet of substrate surface of a layer of the conductive polyelectrolyteof the invention exhibits low resistivity.

EXAMPLE 6 To a solution of 4 grams of polyvinyl alcohol in 200 cc ofwater was added to a solution of 1 gram of homopolymer of Example 1 in10 cc of water. The two solutions were stirred until a homogenousviscous material was obtained. The mixed solution after casting on aglass plate yielded an elastic film. At 20 percent humidity, the surfaceresistivity of the film was found to be 4.9 X 10 ohms/cm? EXAMPLE 7 Aninsoluble cross-linked hydrogel was prepared from an aqueous solutioncontaining 40 weight percent polyvinylalcohol, 40 weight percentpolyacrylic acid, and 20 weight percent of the homopolymer of Example 1in water. A film was cast from the solution. The cast film was thencross-linked by heating at C for 10 minutes. The surface resistivity at20 percent humidity of the cross-linked film was 2 X 10 ohms/cm? In thepreparation of a star polymer the polyamine or polyhalide is firstdissolved in a highly polar solvent such as dimethylformamide (DMF)dimethyl-sulfoxide (DMSO), methanol and their mixtures with water. TheAB monomer is then added to this solution in a substantialstoichiometric excess and heated to a temperature from 40 to 100C. Thestar polymer is recovered by evaporating solvent. Specific examplesfollow:

EXAMPLE 8 EXAMPLE 9 A tetrafunctional tertiary amine of the formula:

H-COO CH 3 C 0 CH H EXAMPLE Four solutions were prepared in 4:1 byvolume DMF- H O containing (A) the compound of Example 8, (B) thecompound of Example 9, (C) 2,4,6-tri-(chloromethyl)-mesitylene and (D)1,2,4,5-tetra-(chloromethyl)- benzene. 50 cc portions of the solutionswere added to DMAP C1 in the following proportions:

Table I Weight of Weight of Solution Compound, grams DMAP Cl. grams A0.044 12.6 B 0.034 12.6 C 0.050 12.6 D 0.060 12.6

The mixtures were heated at 54C for 7 days. A small amount of water wasthen added to dissolve some insoluble material formed during thereaction period. All the samples were rotary evaporated to dryness andthoroughly washed with acetone and dried in a vacuum oven at 40C for 4days. The yield of all samples after drying-was 100 percent. Theintrinsic viscosities of the materials determined in 0.4 M KBr aqueoussolution were as follows:

Table II Sample [1;], 0.4 M KBr A 0.15 B 0.14 C 0.18 D 0.15

To fonfirm the presence of the star polymer, one gram of Sample D wasdissolved in methanol. 0.05 grams of 1,4-dibromobutene was added and themixture was heated at 60C for ten minutes. A gel was formed which wasinsoluble in water as well as common Organic solvents. The formation ofthe gel by crosslinking the tertiary amine terminated branches with thereactive bromo groups served as evidence of the presence of the brancheson the Sample D material.

EXAMPLE 1 1 Of the star polyelectrolytes of Example 10, A-D were testedas flocculation agents for clay suspensions in accordance with theprocedure of Example 5. The

optimum dosage of the star polyelectrolytes was ug/l as compared to 60,ug/l for the commercial mate- 5 rial. 4

The comb-like structure of the branched polyelectrolytes of thisinvention also forms a material having a plurality of multiple chargedbranch side chains. The high concentration of charges provides superiorflocculation action for colloidal impurities in water purification.Higher molecular weight materials can be more readily achieved bybranching than by linear polymerization. Four 25,000 molecular weightlinked chains are the equivalent of a single linear 100,000 molecularweight polymer.

In the branch polymerization the first step is addition of a single ABgroup to the polymeric backbone as illustrated below withpolyvinylbenzylchloride:

+ nMAPc1--% 0 The clatom on the adduct is then available for chainpropagation with a further molecule of DMAP Cl to form a polymeric chainof the comb-like structure.

When a tertiary nitrogen is pendant from the polymer backbone, such asin polyvinyl pyridine, the AB monomer adduct will have a structure ofthe formula:

CH CH Similarly polydimethylaminoethylmethacrylate will form adducts ofthe formula:

Further AB addition will extend the branch chain which will terminate ina dimethylamino group.

In the procedure in which the AB monomer adduct is formed initially, itis preferred that the equivalent ratio of AB monomer to polymer be 111with respect to the A or B reactive functionality of the polymer. Theadduct formation is preferably conducted at ambient temperature in ahighly polar solvent such asDMF- methanol.

The adduct is precipitated in acetone and dried. Although neither thesubstrate polymer or the AB monomer are soluble in water, the adduct iswater soluble. The dried adduct is then dissolved in water andadditional monomer added. The soluble adduct polymer is found to act asa dispersing agent for the added AB monomer.

It is again preferred to conduct the linear AB polymerization in absenceof oxygen which favors higher molecular weight products. Heating thereaction mixture to a temperature between 80-l C accelerates thereaction. The reaction is complete when a viscous solution or solid cakeis formed. The mixture is freeze dried and water removed.

The two-stage reaction can also be conducted in bulk in the presence ofexcess AB monomer. The excess monomer will act as a solvent or diluentfor the adduct. In the first step conducted at ambient, the adduct willform utilizing one unit of AB monomer per unit of reactive group on thepolymer. The temperature is then raised and head-to-tail ABpolymerization will proceed without the need to add more monomer.

Another technique is the attachment of preformed linear polymeric chainsof AB monomer to the substrate polymer. This reaction can be conductedin highly polar solvent such as DMF-methanol and at room temperature.

The reaction must be carefully conducted in order to obtain a watersoluble branched polymer. If the reaction mixture of substrate polymerin DMF-methanol contains excess AB monomer and is heated to atemperature above 80C. an insoluble product is formed. However, a watersoluble branched polymer is formed if this reaction is conducted inwater or methanol.

The linear polymerization in the two-stage process must be carried outin the presence of water or methanol to assure a water soluble productexcept in the case of a bulk reaction.

EXAMPLE 1 2 3 l .g of polyvinylbenzylchloride were added to a 100 ccflask together with 26 grams of DMAP Cl. The reaction mixture wasstirred at room temperature for 30 minutes, until the adduct formed as aprecipitate which was then diluted with 60 ml of water. The solutionformed was then heated in the presence of nitrogen for 2 hours at 100C,during which the linear polymerization of the branch chains occurred dueto the excess of the monomeric material present. The solution was thenfurther diluted with 250 cc of water and freeze dried. The dried solidend product was soluble in water, methanol and 0.1 M sodium nitrate. Thedry product, on heating at 60C for 2 days, became, partially insolublein water. Heating at 100C for the same period rendered the productcompletely insoluble in water.

The intrinsic viscosity of the formed product was found to be 0.38 in0.4 M KBr. Gel permeation chromatography showed a single peak whichindicated only a single species was present which was assumed to be thebranched polyelectrolyte. Furthermore. when the same reaction wascarried out with dimethylaminopropylchloride alone under identicalconditions the intrinsic viscosity did not exceed 0.2.

When the reaction was carried out in absence of nitrogen gas only lowintrinsic viscosity (0.l) products were obtained.

EXAMPLE 13 Six grams of poly 4-vinylpyridine was dissolved in 60 ml ofDMF. 8 grams of dimethylamino-n-propylchloride were added to thesolution. The mixture was then heated at C for 18 hours under nitrogenatmosphere.

The adduct was isolated as a low molecular weight polymer in an amountof 13.8 grams. The adduct was soluble in methanol, water and 0.1 Msodium nitrate and insoluble in acetone, DMF, and 0.4 M KBr. Theintrinsic viscosity in 0.1 M NaNO was 0.233.

EXAMPLE 14 Five grams of the product of Example 13 was dissolved in 16ml of water. To this solution was then added 26 grams ofdimethylamino-n-propylchloride. The mixture was heated to C for 4 hoursunder a nitrogen atmosphere. A green solution was precipitated inacetone and the product dried in a vacuum oven at 30C overnight. 30.2grams of a product was obtained. The product was soluble in 0.4 M KBr. HO, MeOH and 0.1 M sodium nitrate. The intrinsic viscosity in 0.1 Msodium nitrate was 0.319.

EXAMPLE 15 An AB homopolymer was prepared having an intrinsic viscosityof 0.024 and was synthesized in accord with the method set forth inExample 2 above. 2.5 grams of the homopolymer ofdimethylaminopropylchloride were dissolved in 30 ml methanol to whichwas then added 32 ml of DMF. A second separate solution was preparedcontaining 0.20 grams of polyvinylbenzylchloride having an averagemolecular weight of 40,000 dissolved in 2.2 ml of DMF. 2 ml of methanolwere added to the second solution. The second solution of the backbonepolymer was added to the homopolymer solution drop-wise with mixing. Themixture was allowed to react at room temperature for 24 hours. Thesolvent was then removed by vacuum evaporation. The resulting polymerweighed 2.7 grams and was not soluble in H O, methanol and DMF.

EXAMPLE 16 EXAMPLE 17 An insoluble cross-linked hydrogel film wasprepared from an aqueous solution containing 40 weight percentpolyvinylalcohol, 40 weight percent acrylic acid, and

'20 weight percent of the branch polyelectrolyte of Example 14.Crosslinking was achieved by heating a cast film of the material at 100Cfor 10 minutes. The surface resistivity at 20 percent humidity for thefilm was 4.4 X 10 ohms per square.

EXAMPLE 18 A typical starch barrier coated raw paper stock was coatedwith a composition consisting of 50 parts of a reprographic grade clayconventionally utilized for making reproduction paper, 25 parts ofpolyvinylalcohol and 25 parts of the branch polyelectrolyte of Example14 on a basis of 3 pounds of the composition per 3,000 square feet ofpaper surface. The surface resistivity of the coated paper at relativehumidity was found to be 10 ohms/square.

EXAMPLE 19 0.22 gm of polyethylene imine (.005 mole) were mixed with30.35 gm of DMAP cl (0.25 mole). Ten ml of water were added and themixture heated for 2 hours at 100C. An additional 10 ml of water wereadded and the mixture heated to 100C for another hour. A further 10 mlof water were added and heating continued for an additional 17 hours.The isolated branch polymer had an intrinsic viscosity of 0.15 dl/g.

High purity DMAP Cl monomer was prepared according to the followingprocedure.

EXAMPLE 20 DMAP Cl monomer was isolated from its hydrochloride salt byreaction with NaOH. 100 g (0.633 mole) of 3-dimethy1amino-n-propylchloride hydrochloride was dissolved in the minimum quantity of water,cooled in an ice bath and 200 ml of 20% NaOH solution added dropwisewith vigorous stirring. The monomer was then extracted with severalsmall portions of ether. The ether extracts were combined, washed twicewith water and then dried over anhydrous magnesium sulfate. After adrying period of 12 hours, the ether solution was filtered and thenrotary evaporated. The monomef, together with a small quantity ofremaining ether, was finally vacuum distilled. The fraction distillingbetween 22 and 25C, at 5 mm Hg pressure, was collected and stored-at 0Cuntil required. Both NMR and IR spectra confirmed the structure andpurity of the monomer prepared as described above.

The monomer was allowed to polymerize at 41C for 5 days in varioussolvent systems. The initial monomer concentration was kept constant at1.0 molar. The results are summarized in Table III.

"Dimethylsulfoxide Table III shows that for the solvents tested thehighest intrinsic viscosity was achieved in the DMF/I-I O system. Themonomer was therefore allowed to polymerize at various temperaturesusing 4:1 DMF/H O as solvent and an initial monomer concentration of 1.0mole/l. The reaction was allowed to continue until titration ofunreacted end groups indicated that the polymerization was complete. Theresults are summarized in Table IV.

TABLE IV Effect of Temperature Temperature C Z Yield (17) in 0.4M uq.KBr dl/g The yields over 100% are due to insufficient drying time. Forthis solvent system, the molecular weight decreases if thepolymerization is carried out at a tem perature above about C.

The monomer was allowed to polymerize in either 4:1 DMF/H O or 4:1DMSO/H O at 54C, using various initial monomer concentrations and a 48hour reaction time. The results are shown in Table V.

TABLE V Effect of Initial Monomer Concentration Tables III, IV and Vindicate that for relatively high molecular weight the optimum solventsystem is the DMF water mixture at temperatures in the range of 50 to Cand at a concentration of 2 to 3.5 moles/l. The insolubility of thefinal polymer in DMF water mixtures could be a reason for the difficultyin achieving intrinsic viscosities higher than 0.2 dl/g in 0.4M KBrsolutions. The polymerization was therefore investigated in pure waterin which the polymer is miscible in all proportions.

The 3,3-ionene chloride (AB polymer) was obtained by heating a stirredsuspension of AB monomer in water. Table VI, below, illustrates theeffects of air, oxygen and nitrogen on the yield and intrinsic viscosityof the polymer formed in the aqueous system.

TABLE VI Polymerization of AB monomer in water in presence and absenceof air The aqueous polymerization system (Table VI) thus offers aconvenient technique for the synthesis of 3,3 ionene chloride withviscosities higher than 7 those achieved in other solvents provided theprocess is car ried out in absence of air and at high monomerconcentration. Additional studies of monomer concentration and reactiontime confirmed the above conclusion as illustrated in Table VII, whichfollows.

TAB LE VII Polymerization of AB monomer in water Effect of reaction timeand monomer concentration at 100C The aqueous polymerization system canalso be carried out at higher temperatures than the DMF/H O system. Athigher temperatures in the presence of DMF, side reactions occurresulting in a lower intrinsic viscosity. Higher molecular weights arefavored at higher concentration in water. The initial monomerconcentration is at least 4 mole/1 and preferably at least 6 mole/l. Ateven higher molecular weight was obtained by a multistage polymerizationprocedure in which the initial monomer concentration is at least 4mole/l and polymerization proceeds for a first period to less than 100%but more than 50% conversion to polymer. The polymerization mixture isthen diluted by diluting the monomer concentration as initiallydetermined by at least 10% and polymerization continued to completion.

A very high molecular weight polymer was obtained by the followingprocedure.

EXAMPLE 21 DMAP Cl monomer (52g) and water (16 ml) were combined to forma 7.22 molar mixture. The mixture was heated at 100C in the presence ofnitrogen for four hours. A solid material formed at the end of 4 hours.Another 16 ml of H 0 was then added (dilution to 5.9 molarity on aninitial basis) and the heating was continued for another 20 hours.

The 3,3-ionene chloride was then isolated. The intrinsic voscosity in0.4M KBr was found to be equal to 0.25 dl/g which corresponds to amolecular weight of 63,000 as detennined by the technique discussedbelow.

When this polymer is compared to the highest molecular weight polymershown in Table VII, it is evident that reaction time has been decreasedfrom 148 hours to 24 hours and the molecular weight of the product ishigher at the shorter reaction time.

The molecular weights reported by the present inventors have beendetermined from the intrinsic viscosity molecular weight relationship inaqueous 0.4M KBr by 16 means of light scattering and can be expressedapproximately by:

1 11= 194 10)M" Further details of the procedure are discussed by Cassonand Rembaum, Macromolecules 5, Jan-Feb. 1972.

Reaction rates, for the homopolymerization of the DMAP Cl monomer. weremeasured by means of NMR spectra, determined at 60 or 220 megacycles orby titration of unreacted tertiary amine end groups. An aliquot of thereaction mixture was added to excess dilute hydrochloric acid and theunreacted acid titrated potentiometrically with dilute sodium hydroxidesolution.

The rate of polymerization was followed by the previously describedtitration technique or by monitoring the NMR resonance peaks, either dueto decreasing concentration of the protons or increasing concentrationof as a function of time. The validity of this procedure issubstantiated by a careful analysis of high resolution 220 mc NMRspectra of the monomer and polymer; however, the actual rates wereestablished using a 60 mc NMR spectrometer. The spectral changesoccurring with time were determined. The rates of polymerizationmeasured by means of the NMR technique agreed with those obtained bypotentiometric titration of the chloride ion within il0%. The kineticresults reflect the increase in rate at room temperature as thedielectric constant of the solvent increases. The same effect is shownat 55C.

The molecular weight of the polymer increased with time of conversion asexpected from a step growth polymerization system. The intrinsicviscosities determined in 0.4M aq. KBr as a function of polymerizationtime as shown in Table VIII.

TABLE VIII Intrinsic viscosities of AB polymer isolated from separatebatches of 1 molar AB monomer and polymerized at 54C in DMF/H o (4:1 asa function of time Time (1 in 0.4M aq. KBr (hrs) dl/g The highcrystallinity of different ionene bromides was established by theexamination of X-ray diffraction patterns using CuKaradiation. Similarresults were obtained with 3,3-ionene chloride. The X-ray diffractionpatterns show that the high crystallinity persists in low and highmolecular weight polymers and that the same is also true for 3,3-ioneneperchlorate and 3,3- ionene triiodide.

A comparison of specific reduced viscosity of 3,3 and 6,6-ionenechloride as a function of ionic strength indicates that an ionenecontaining a large number of positive charges in its chain undergoesmore extensive coiling with increasing ionic strength than thecorresponding ionene with comparatively low numbers of positive charges.This is evidenced by comparing the [17],, of 3,3-ionene chloride withthat of 6,6-ionene chloride as a function of KBr concentration. Thecomparison also confirms the effect of decreased viscosity in KBr ascompared with KCl solutions.

The intrinsic viscosities of polymer samples isolated from separatebatches of 5.91 molar DMAP Cl monomer polymerized at 100C in water areshown as a function of time in the following table:

TABLE IX Intrinsic Viscosity Time. hrs. in 0.4M KBr. dl/g EXAMPLE 22 Theoptimum concentration of polyelectrolyte for dewatering waste activatedsludge was first determined. The optimum amount of each polyelectrolytewas then added to a 500 ml sample of sludge containing 2% sludge solids,stirred at high velocity for seconds, poured into the Buchner funnel andthe vacuum activated. The results follow:

TABLE X Amou- Water. Time.

Polyelectrolyte mg/l ml sec.

None 72 l20 Homopolymer (Ex. I) 1 100 99 Tetraamine Star (Ex. lOA) 500I00 90 Polyethylene lmine Branch (Ex. l9) 400 I00 85Polyvinylbenzylchloride Branch (Ex. 12) 200 100 52 EXAMPLE 23 200 mlsamples of digested sludge containing 3.5% solids were subjected to theprocedure of Example 22. The results follow;

It is apparent that the effectiveness of the polyelectrolytes asdewatering agents increases as the charge density and amount ofbranching increases from homopolymer to star to branch, comb-polymer.

It is to be realized that only preferred embodiments of the inventionhave been described and that numerous substitutions, alterations andmodifications may be made without departing from the spirit and scope ofthe invention as defined in the following claims.

What is claimed is:

1. An article of manufacture comprising an inert substrate sheetcontaining from 0.1 to 5 pounds per 1,000 square feet of substratesurface of a layer of a water-soluble, conductive polyelectrolyte of theformula:

where Z is bromo, chloro or iodo and n is an integer such that theintrinsic viscosity is at least 0.20 dl/g as determined by means oflight scattering in 0.4 molar KBr according to the relationship:

1; 2.94 X I0)M" where 1 intrinsic viscosity and M is molecular weight.

2. An article according to claim 1 in which the polyelectrolytecontaining layer is in the form of a conductive hydrogel containing2095% by weight of a gel forming polymer selected from the groupconsisting of polyvinyl alcohol, polyacrylic acid, alginic acid andpolyether.

3. An article according to claim 2 in which Z is chloro and the gelforming polymer is polyvinyl alcohol.

4. An article according to claim 3 in which the gel is a cross-linkedhydrogel of polyvinyl alcohol and polyacrylic acid.

5. An article according to claim 3 in which the substrate is paper.

6. An article according to claim 5 in which the layer further containsreprographic grade clay.

7. A method of forming a coated article comprising the step of applyingto the surface of an inert substrate sheet a layer containing from 0.1to 5 pounds per 1,000 square feet of a conductive polyelectrolyte of theformula:

where Z is bromo. chloro or iodo and n is an integer such that theintrinsic viscosity is at least 0.20 dl/g as determined by means oflight scattering in 0.4 molar ll) KBr according to the relationship:

1, 2.94 x mwM' and the substrate is paper.

Patent No. 3, 927, 242

Inventor(s) Dated December 16, 1975 Alan Rembaum; Shiao-Ping S. Yen

'It is certified that error appears in the above-identified patent: andthat said Letters Patent are hereby corrected as shown below:

Column Column Column Column should Column Column Column Column Column10, Column 12, Column 15, Column 15,

[SEAL] line line line line ad -dibromobutene-.

line 5, "an" should read -can-. line 20, "or" should read -of-. line 25,"about" should read above--.

line 58, "fonfirm" should read --confirm.

line 32, "Clatom" should read -Cl atom-.

line 18, after "under" insert -a-.

line 35, "At" should read -An--.

line 57, "voscosity" should read viscosity-;

Signed and Scaled this thirtieth D f March 1976 Arrest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN (mnml'xsiuner ufPatenrsand Trademarks

1. AN ARTICLE OF MANUFACTURE COMPRISING AN INERT SUBSTRATE SHEETCONTAINING FROM 0.1 TO 5 POUNDS PER 1,000 SQUARE FEET OF SUBSTRATESURFACE OF A LAYER OF A WATER-SOLUBLE, CONDUCTIVE POLYELECTROLYTE OF THEFORMULA:
 2. An article according to claim 1 in which the polyelectrolytecontaining layer is in the form of a conductive hydrogel containing20-95% by weight of a gel forming polymer selected from the groupconsisting of polyvinyl alcohol, polyacrylic acid, alginic acid andpolyether.
 3. An article according to claim 2 in which Z is chloro andthe gel forming polymer is polyvinyl alcohol.
 4. An article according toclaim 3 in which the gel is a cross-linked hydrogel of polyvinyl alcoholand polyacrylic acid.
 5. An article according to claim 3 in which thesubstrate is paper.
 6. An article according to claim 5 in which thelayer further contains reprographic grade clay.
 7. A method of forming acoated article comprising the step of applying to the surface of aninert substrate sheet a layer containing from 0.1 to 5 pounds per 1,000square feet of a conductive polyelectrolyte of the formula:
 8. A methodaccording to claim 7 further including the step of forming said layer bydispersing the polyelectrolyte in 20-95% by weight of a gel forMingpolymer selected from the group consisting of polyvinyl alcohol,polyacrylic acid, alginic acid and polyether.
 9. A method according toclaim 8 in which Z is chloro, the gel forming polymer is polyvinylalcohol and the substrate is paper.